In this photo taken from a video monitor at the Union County Courthouse in Jonesboro, Ill., Anthony Garcia, an Indiana doctor suspected in the killings of three adults and an 11-year-old boy in Nebraska, appears before Judge Mark Boie in a brief court appearance Tuesday. Boie deferred until Wednesday a hearing on Garcia's extradition to Nebraska until after the man had a chance to confer with an attorney coming from the Chicago area. (ASSOCIATED PRESS / The Southern, Paul Newton)

OMAHA, Neb. (AP) — An Indiana doctor accused of killing four people with ties to a Nebraska medical school that fired him was denied medical licenses in at least two states after the dismissal from Creighton University more than a decade ago.

Authorities have not disclosed a motive in the slayings, except to note the firing. But documents show that the dismissal for erratic behavior in 2001 had long-lasting effects on Anthony Garcia's career.

The slayings took place in two separate attacks five years apart.

The 40-year-old physician, who appeared before an Illinois judge Tuesday, is accused of killing a pathology professor and his wife earlier this year, as well as the 2008 stabbings of another professor's son and housekeeper in a neighborhood near the home of billionaire Warren Buffett.

Documents provided Tuesday by an Indiana medical licensing board show Garcia was denied a medical license in Louisiana a month before the 2008 killings. The May killings occurred within months of Garcia being denied an Indiana license.

Garcia, who now lives in Terre Haute, Ind., was arrested by Illinois State Police on Monday during a traffic stop in Union County, in southern Illinois.

The arrest came two months after Creighton professor Roger Brumback was fatally shot and his wife stabbed to death in their home. Back in 2008, the son of another pathology professor, William Hunter, and his housekeeper were stabbed to death in an affluent Omaha neighborhood.

Brumback and Hunter fired Garcia. Neither police nor Creighton officials have detailed the behavior that led to the dismissal.

But a letter sent by Brumback in January to the Indiana Professional Licensing Agency said Garcia was fired after attempting to sabotage a fellow Creighton resident. Documents filed with the letter showed that Garcia called the wife of the colleague — who was in the midst of a high-pressure test — insisting that the colleague return to the university's pathology department.

Garcia quit a previous residency to avoid a disciplinary hearing for yelling at a radiology resident. He was fired from subsequent residence programs after failing to obtain a medical license because he omitted problems at earlier programs.

Detectives had few leads in the first killings. Eleven-year-old Thomas Hunter and the housekeeper, Shirlee Sherman, were probably not the intended targets of the 2008 attack, and investigators believe Garcia acted alone, Omaha Police Chief Todd Schmaderer said.

Witnesses reported seeing a well-dressed, olive-skinned man parking a Honda CR-V about a block from the Hunter home and walking up to the door with a case of some type.

Police released a sketch based on witnesses' recollections, and an award for information climbed to more than $50,000. But police were unable to develop any solid leads, despite an airing of the case on "America's Most Wanted."

Seven years had passed from the time Garcia was fired until the killings of Thomas and his housekeeper.

"For most people, that's such a long time in between," Omaha police spokeswoman Lt. Darci Tierney said. "It's probably understandable why his name wouldn't come up."

Tierney said detectives made progress in the case after the slaying of the Brumbacks, when an FBI task force was created to look into the slayings.

It was unclear where Garcia finished his medical residency after being fired from Creighton.

Since 2003, he has held medical licenses in California, Illinois and Indiana, but his temporary Indiana license expired in January, according to public records.

Garcia was briefly employed in 2009 as an independent contractor for a Chicago service that offered home doctor visits to the elderly. The physician who employed Garcia described him as "mild-mannered" and "a really nice guy."

"He was never aggressive. He was never belligerent. He was never angry or losing his temper or impatient," said Dr. Benjamin Toh.

But a neighbor in Terre Haute, Benjamin Fairhurst, said police were called when Garcia twice brought flowers to two college-aged women in the neighborhood.

"He was strange, I will say that," said Fairhurst, a retired bank president.

Garcia told neighbors he was a doctor at the federal prison in Terre Haute.

Fairhurst said Garcia came and left home at strange hours and never had any visitors. But he waved as he passed by and wished neighbors happy holidays, Fairhurst said.

"I had no idea he was involved with this stuff," he said. "But now as I look back I can kind of see it."

When he was arrested, Garcia appeared to be intoxicated and had a .45-caliber handgun, police said. He was jailed without bond.

Garcia appeared in court in Jonesboro, Ill., about 120 miles southeast of St. Louis. A judge deferred questions about any possible extradition to Nebraska until Garcia confers with an attorney, according to a report by the Southern Illinoisan newspaper in Carbondale.

Allison Motta, a Chicago-area attorney who said she was contacted by Garcia's family to represent him, declined Tuesday to discuss the case with The Associated Press as she was traveling to southern Illinois.

Another court hearing was scheduled for Wednesday.

Neighbors of the Brumbacks were still digesting the news of Garcia's arrest.

"It saddens us to think that something like this could happen, and no one saw anything," said Carol Fettin, who lives three houses down from the Brumback home. "We racked our brains, trying to come up with something."

Court records show Garcia filed for bankruptcy in 2005, saying he was more than $81,000 in debt. The only assets he listed were about $1,000 in cash and a 2000 Honda CR-V.